Capacitor housing



Feb. 21, 1950 w. J. STEEN CAPACITOR HOUSING Filed Oct. 7, 1947 JwucmforWILLIS J. STEEN s lvninvneiii Ill/Ill FIG. l

Patented Feb. 21, 1950 CAPACITOR HOUSING Willis J. Steen, Chicago, Ill.,assignor to the United States of America as represented by the Secretaryof the Navy v Application October 7, 1947, Serial No. 778,442

1 Claim.

The present invention relates to a capacitor and to a process of makingthe same. More particularly it relates to a metal-incased, annularcapacitor and to a process of making the same whereby the capacitor ishermetically sealed.

An object of the invention is to provide an annular capacitor which ishermetically sealed in a casing to prevent the entrance therein of dirt,moisture and corrosive gases, and to protect it from mechanical injury.

Another object of the invention is to provide a hermetically sealed,metal-incased, annular capacitor in which the terminals are similarlysealed hermetically to the metal case by means of sleeves, which alsoinsulate the said terminals electrically from the metal enclosure.

Another object is to provide an eflicient process of making suchenclosures, sealing the capacitor elements therein, and providingterminals which are not only hermetically sealed to the enclosures butalso insulated electrically therefrom.

A still further object is to provide an improved capacitor, simple inconstruction, economical of manufacture and effective in operation.

Other objects and advantages of the invention will become apparent fromthe following description, taken in connection with the accompanyingdrawing, and it will be understood that many changes may be made in thearrangement and details of parts described without departing from thespirit of the invention as set forth in the accompanying claims. I,therefore, do not wish to be limited to the exact details shown anddescribed, as the preferred form only has been shown by way ofillustration.

In the accompanying drawing:

Figure 1 is a top plan view of a capacitor embodying the presentinvention;

Figure 2 is a sectional view taken on line 2-2 of Figure 1;

Figure 3 is a sectional view taken on line 3-3 of Figure 2;

Figure 4 is an enlarged detail sectional view taken on line 4-4 ofFigure 1, illustrating the sealing and insulating arrangement for theupper edge of the capacitor; and

Figure 5 is a enlarged sectional view, similar to Figure 4, but taken,however, through one of the terminals.

The capacitor herein described and illustrated comprises a capacitorelement l1 encased in a housing formed from two cylindrical members I0and 13. The outer member is preferably a seamless-drawn metalcylindrical shell H, open at both ends, and having an. integral,inwardlyextending flange l2 at its base. The inner member I3 is likewisepreferably a seamless-drawn metal cylindrical shell H, open at bothends, and having an integral, outwardly-extending flange ii at its base.The outer diameter of the flange i5 is sufficiently less than the boreof the shell I I to permit the two members l0 and (3 to be assembled asshown in Figure 2.

The two flanges may be secured to one another in any suitable manner andpreferably by soldering along the edge at l5 as noted in Figure 2. As analternative the flanges may be welded by either a continuous weld or byspot welding. In the latter event a suitable coating would have to beapplied along this edge, if a hermetic seal is required.

The capacitor element ll itself consists of two continuous strips ofconducting material or foils l8 and I9 alternating with two strips ofdielectric 20 and 2! which are wound to form a hollow cylinder that willfit into the annular space between the shells It and It. While twocomplete windings are illustrated in Figure 3, it should be understoodthat the accompanying drawing is diagrammatic and that any number ofsuch windings may be employed, as desired. In order to secure acapacitor that is as compact as possible, it is preferred to wind theconducting foils l8 and 19 with the interposed dielectric strips 20 and2! directly upon the outer surface of the cylindrical shell H. Whenutmost compactness is not of paramount importance, however, it may befound expedient to assemble capacitor element ll before inserting itinto the housing or metal container, which in that case may be finishedpreviously.

The foils, l8 and H are preferably so interposed between the dielectricstrips 20 and 2| that the lower edges of the foils do not extend as faras the dielectric strips, whereby the lower edges of the latter serve asspacers to preclude contact between the lower edges of the foils and thebase of the metal container. As an alternative construction, the bottomedges of the conducting strips and the interposed dielectrics may bemade flush and short circuiting of the capacitor foils through the metalcontainer prevented by coating at least the lower part of the capacitorIT with some appropriate material such as parafiin. Similarly, the outerlayer IQ of the capacitor assembly is insulated from the metal outershell H of the housing by an outer winding of paper 22 or some othersuitable dielectric. The inner layer of the capacitor assembly I! beingthe dielectric 20, the capacitor is thereby insulated from the metalinner shell M the housing without the need of any by the tubes 25 ofglass or plastic through which they pass. The terminal 25 makeselectrical contact with the conducting strip l9 through the connectorstrip 28. The connector 28 extends from a connection with the terminal25, as by the solder joint 29 illustrated in Figure 5, downwardlybetween the windings of the dielectric 2i and the foil IS. The pressureof the windings is ordinarily sufllcient to retain the connector stripin position and in electrical contact with the conducting foil IS. Theterminal 24 is similarly connected to the foil i8 by means of theconnector 21. As an alternative construction, the terminals themselvesmay extend downwardly between the windings of the capacitor, therebyeliminating the connector strips 21 and 28.

A suitable plastic insulating material 23 is applied to the upper edgeof the capacitor element I! to seal it and to insulate the top edges ofthe conducting foils l8 and 19. The terminals and 25 and the connectorstrips, ii employed, projecting through the material 23, are similarlyinsulated thereby. The upper edges of the cylindrical shells ii and Mare bent or crimped together, the joint being made tight by solder M, asillustrated in Figure 4. Where the terminals 24 and 25 emerge from themetal housing, the upper edges of the cylindrical shells are similarlycrimped about the insulating tubes 26 through which the terminalsextend.

4 It is apparent that, while the. capacitor housing of the embodiment ofthe invention described and illustrated is disclosed as being composedof metal, the housing members Ill and i 3 1 may be constructed ofplastic or some material other than metal, similarly secured to eachother and sealed by conventional means.

I claim:

A metal housing for a capacitor, including a pair of cylindricalmembers, one oi said members comprising an outer shell and the other aninner shell, flanges at the corresponding lower ends of the cylindricalmembers and extending towards each other and in overlapping relation,means for fastening and hermetically sealing said flanges together todefine a closure for the lower end 01' the housing, an insulatingcomposition in the upper end of the housing to insulate 9. capacitor insaid housing from the metal housing, a pair of terminals projectingthrough the i sulating composition, an insulating tube abo t each of theterminals, the upper edge portio s of said members being crimpedtogether and about said insulating tubes, and a bead fastening andhermetically sealing said crimped edges together.

WILLIS J. STEEN.

REFERENCES CE'KED UNITED STATES PATENTS Name 4 Date Albert Feb. 4, 1936Number

